The mayor of a city in Poland has died after being stabbed onstage during a charity event Sunday.

Pawel Adamowicz, who has been the mayor of Gdansk for 20 years, was attacked while live on television. The suspect who rushed the stage was recently released from prison, BBC reports. Adamowicz underwent five hours of surgery but died from his injuries, Poland's Health Minister confirmed.

Adamowicz, 53, was attending an annual charity event that raises money for hospital equipment. He was speaking onstage when a 27-year-old with a criminal record stabbed him in apparent revenge for his imprisonment. The suspect said Adamowicz's former Civic Platform party "had wrongfully imprisoned him" and that he was "tortured" in jail, BBC reports via local television footage. He is believed to have used a media pass to get past security, per Al Jazeera.

Adamowicz was re-elected to lead Gdansk, a city of about 500,000 people, for a sixth term in the fall. He had left the Civic Platform party to run as an independent, The Associated Press says. He was known as a progressive supporter of "sex education in schools, LGBT rights and tolerance for minorities," and "often mingled freely with citizens," AP writes. A spokeswoman for the opposing Law and Justice party said Adamowicz's murder should be "absolutely condemned by all" sides of the "political spectrum." Kathryn Krawczyk

"Scholars have struggled to estimate death tolls" after retreating German forces destroyed records at the end of World War II, BuzzFeed News says. So for this study, Tel Aviv University biomathematician Lewi Stone looked at railroad records during the Holocaust's deadliest murder campaign. The yearlong Operation Reinhard saw 480 railway deportations from Polish towns, but three months of the campaign were especially deadly. About 1.5 million Jews were killed during just 100 days in 1942, the study shows.

This new finding reveals a "hyperintense kill rate" during Operation Reinhard, as the study puts it. While previous estimates put the Holocaust kill rate at an astounding 50,000 murders per month, the death rate may have been up to 10 times higher during those three months. That's about double the monthly death rate of 243,300 during the 1994 Rwandan genocide.

A University of Bern historian suggested the new study's estimates are too high, saying the entire operation killed 1.32 million people, per BuzzFeed News. Still, seeing as "large-scale murder operations in the last 25 years" were possibly "preventable," the study says understanding the Holocaust and other genocides could be "the most important goal of social science."

Friday marked six years since 28 people, mostly children, were killed at Sandy Hook Elementary School. On the same day, another threat to the school forced its evacuation.

At around 9 a.m. Friday, police say the Newtown, Connecticut school received a bomb threat and evacuated everyone inside, local ABC affiliate WCVB reports. Police later said the threat was likely not credible, but school was still canceled for the rest of the day, per local station Fox 61.

A wave of bomb threats were emailed to businesses, schools, and government buildings across the U.S. on Thursday, but were determined to be a hoax. Sandy Hook's threat didn't seem to be connected to these widespread threats, police told Fox 61. The building where the Sandy Hook shooting happened in 2012 was previously demolished and a new school was rebuilt. Police began sweeping the existing school after everyone was evacuated.

Local gun control group Newtown Action tweeted the news and asked readers to "please stand with our community as we attempt to survive another tragic anniversary." Sen. Chris Murphy (D-Conn.) quickly responded with the tweet below. Kathryn Krawczyk

The average age of the children sent to emergency rooms after being shot was just 14.8 years old, the study found. But just 39 percent of these incidents were accidents, while another 49 percent were "intentional assaults," the Times notes. The rate of children being shot was at its highest in 2006 and fell until 2011, but then rose again each year until the study's data collection ended in 2014.

An "overwhelming majority" of these gunshot victims were male, and especially likely to be between the ages of 15 and 17, the Times reports. And overall, 6.6 percent of all young gunshot victims ended up dying of their injuries, the study found. Treating these victims cost an average of $270 million per year, with patients who required additional hospital care accruing the largest costs. The study only drew from data collected in hospitals, so there's no telling how patients' health is affected in the long term, or how much money they spend on recovery once they're discharged. Read more about the study at the Los Angeles Times. Kathryn Krawczyk

Attorneys from the Center for Human Rights and Constitutional Law said that children at the Shiloh Residential Treatment Center in Texas and other migrant shelters run by the federal Office of Refugee Resettlement say they are still being administered "psychotropic drugs without informed parental consent or court order." The government is "almost certainly not complying" with a California federal judge's July 30 order, the lawyers said, offering written statements from four children and one child's aunt about the medication they are being given inside Shiloh.

A 17-year-old whose name was redacted said they are given three medications in the morning, including Zoloft, and four at night. The teen sees a doctor every two weeks, and "he tells me the drugs I need to take, but doesn't explain why," the teenager wrote on Oct. 18. "The drugs make me feel really tired and sluggish. I have trouble concentrating in class. Sometimes I have stomach pain and a lot of headaches. Sometimes I feel numb on one side of my body. I tell the doctor about these problems, and he says it is all normal." The Department of Health and Human Services, which oversees the Office of Refugee Resettlement, told CBS News the agency will submit a reply to the court filing on Friday. Catherine Garcia

In a case of mistaken identity, police officers in Aurora, Colorado, fatally shot a homeowner just moments after he shot and killed an intruder.

The officers were responding to a call on Monday from a woman who said someone was breaking into her house, USA Today reports. When they arrived at the home, it was a "very chaotic and violent scene," and the officers heard gunshots. Almost immediately, they encountered an armed man. An officer shot him, and he was rushed to a hospital, where he died from his injuries.

It was quickly determined the armed man lived in the house, and had just shot and killed the intruder. "This is a very heartbreaking and tragic situation for everyone involved," Aurora Police Chief Nick Metz said in a statement. "We are providing assistance through our victim advocates to help the family of the deceased resident through this very difficult time." Catherine Garcia

An undocumented immigrant from Honduras died by suicide May 13 inside a jail cell in Starr County, Texas, a U.S. Customs and Border Protection spokesperson said Sunday.

Marco Antonio Muñoz, 39, was arrested by Border Patrol agents May 11 in Weslaco, Texas. Authorities said he was taken to a processing center, where he became "disruptive and combative," and was moved to a jail. There, he died by self-strangulation. Authorities said he was checked on by officers every 30 minutes, and there was a camera inside his cell.

Border Patrol agents who spoke to The Washington Post said Muñoz had a breakdown when he was separated from his wife and 3-year-old son. An agent said once Muñoz was told his family would be separated, he "lost it" and "they had to use physical force to take the child out of his hands." The Customs and Border Protection agency spokesperson did not mention anything about Muñoz's family.

The Trump administration has announced it is cracking down on people crossing the border illegally, and in order to prosecute adults that are caught, families are being separated, with parents going to jail and children being placed with the U.S. Office of Refugee Resettlement. Catherine Garcia

Celebrated author and chef Anthony Bourdain, host of CNN's award-winning series Parts Unknown, has died in an apparent suicide, CNN reported Friday. He was 61.

"His love of great adventure, new friends, fine food and drink, and the remarkable stories of the world made him a unique storyteller," the network said in a statement. Bourdain, whom the Smithsonian once called the "the Elvis of bad boy chefs," was in France working on an episode for his show, which explored food and culture around the world, when a friend, French chef Eric Ripert, found him unresponsive in his hotel room.

Bourdain was a chef before his 2000 best-selling book Kitchen Confidential: Adventures in the Culinary Underbelly catapulted him to stardom. He hosted shows on the Food Network and the Travel Channel before joining CNN. Harold Maass